Railroad freight car sidebearing

ABSTRACT

An improved side bearing for railway cars is provided that achieves improved tracking and curving by the limitation of rock of the railway car. The side bearing comprises a base with a generally upwardly extending wall portion. A cap comprising a top section with generally downwardly extending wall portion is provided. The cap extends into or around the wall section of the base. A spring is provided within the base that extends to the underside and supports the cap. A base insert is provided of varying thickness to support springs of the same preselected height to provide preselected varying load capacities.

BACKGROUND OF THE INVENTION

The present invention relates to an improved side bearing for mounting on a railway car truck bolster that provides improved control to limit rock and roll characteristics of the railway car in service.

In a typical railway freight train, such as shown in FIG. 1, railway cars 212, 214 are connected end to end by couplers 216, 218. Couplers 216, 218 are each received in draft sills 220, 222 of each respective car along with cushioning or draft gear assemblies not shown. Draft sills 220, 222 are provided at the end of the railway car center sill, and include center plates that rest in center plate bowls of railway car trucks 226, 228.

As is better shown in FIG. 2, each typical car truck 226 includes a pair of side frames 230, 232 supported on axle-wheel sets 234, 236. Bolster 238 extends between and is supported on springs 240 mounted on side frames 230, 232. Bolster center plate 224 includes a central opening 242. Side bearing pads 260 are provided laterally to each side of the center plate 224 on bolster 238. Side frames 230, 232 comprise a top member 244, compression member 246, tension member 248, column 250, pedestal 254, pedestal roof 256, wheel axle bearings 258, and bearing adapter 262. Side bearings are commonly used on railroad car trucks. Such side bearings are typically located on the truck bolster such as on side bearing pads 260, but may be located elsewhere on the bolster.

Typical side bearing arrangements are designed to control hunting of the railroad car. As a railroad car travels along the railroad track, a yaw excess motion can be induced in the railroad car truck. As the truck yaws, part of the side bearing is made to slide across the underside of a wear plate bolted to the railroad car body bolster. The resulting friction produces an opposing torque that acts to prevent such yaw motion. Another purpose of railroad car truck side bearings is control or limit the rock or roll motion of the car body. Most prior side bearing designs limited vertical travel of the side bearings. The maximum vertical travel of side bearings is specified in the Association of American Railroad Standards. Such vertical travel has limits based on the allowable height of the freight car and the design loading of the freight car.

Accordingly, it is an object of the present invention to provide an improved side bearing which will be selectably responsive to the design loading of a freight car.

SUMMARY OF THE INVENTION

A side bearing is provided with improved characteristics to enhance the performance of rail cars with selectable side bearings being available based on the design loading of a freight car.

One embodiment of a side bearing in accordance with the present invention includes a base having a bottom portion and a base wall structure extending generally upwards therefrom. The base wall structure forms a base receiving structure with a generally open centrally located top and a smaller diameter opening in the bottom. A spring is positioned in the base receiving structure. A base insert is placed in the base receiving structure and provides support for the spring.

An elastomer spring of a generally cylindrical shape is positioned within the base receiving structure.

A cap of a generally inverted cup structure has a top portion and a cap wall structure extending generally downward from the top portion. The cap wall structure forms the cap receiving structure having an open bottom.

The top portion of the spring extends into the cap receiving structure open bottom to support the cap.

The base is usually a unitary cast steel or cast iron structure, but could be fabricated. The cap structure is also usually a generally cast steel or cast iron unitary structure, but also in certain embodiments could be fabricated.

The spring is usually formed of a urethane polymer, or other suitable elastomer.

The side bearing base insert is usually a unitary structure made of a structural plastic, but could be a metal structure.

At the standard set-up height of 5.0625 inches (12.8 cm), the cap will be supported by and will preload the elastomer spring for an empty railway car. The base insert can be of varying thickness to affect the support height of the bottom of the spring. Depending on the desired load capacity of the freight car, the height of the base insert and compression characteristics of the spring can vary. The elastomer spring will have a selected load rating to increase the spring stiffness during further travel downward into or over the base of the side bearing. By limiting such downward travel of the cap, the rock of the railway freight car, especially in an unloaded condition, is kept within preselected design parameters. A base insert is provided of varying thickness to support springs of the same height to provide preselected varying load capacities.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings,

FIG. 1 is a partial schematic of coupled ends of typical railway freight cars;

FIG. 2 is a perspective view of a typical railway car truck;

FIG. 3 is a side assembled view of one embodiment of a side bearing according to the present invention;

FIG. 4 is a top sectional view of the first embodiment of the assembled side bearing;

FIG. 5 is a cross sectional view of the first embodiment of the assembled side bearing;

FIG. 6 is an exploded view of the first embodiment of the side bearing;

FIG. 7 is a side cross sectional view of the cap of the first embodiment of the side bearing;

FIG. 8 is a side cross sectional view of the base section of the first embodiment of the side bearing.

FIG. 9 is a side cross sectional view of the spring of the first embodiment of the side bearings;

FIG. 10 is a side cross sectional view of a first embodiment of a base insert of the side bearing of the present invention;

FIG. 11 is a side cross sectional view of a second embodiment of a base insert of the side bearing of the present invention,

and FIG. 12 is a side cross section view of a third embodiment of a base insert of the side bearing of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIGS. 3 through 9, a first embodiment of side bearing according to the present invention is shown. Side bearing 10 includes a base structure 12, which is comprised of a bottom portion 22 and a base wall 24 extending generally vertically upward therefrom. Base structure 12 is usually cast steel or cast iron unitary structure, but can be fabricated or machined as well. The shape of base 22 can be circular, somewhat rectangular, or somewhat oval or diamond shaped as the use dictates.

Cap 14 is seen to be comprised of a top portion 26 with a wall structure 28 extending generally downward from the outer edge of cap 14. Again, cap 14 is usually a cast steel or cast iron unitary structure, but can be fabricated or machined as well.

Base 12 is seen to also include a base wall top stop surface 38 which is located at the top of base wall 24. Similarly, cap 14 is seen to include a cap inner stop surface 30 which is formed by an inner surface within cap 14 and is adjacent and complementary to base wall top stop surface 38. An elastomer spring 20 is seen to be formed in a generally cylindrical structure, with a bottom 25 supported on base insert 21 top surface 23. Base insert 21 is a unitary structure, usually comprised of a structural plastic, but is could be comprised of steel. Cap inner center projection 32 is received in opening 27 of elastomer spring 20.

Elastomer spring 20 is a typical polymer elastomer available from companies such as the Steinmetz Polymers, and is seen to be comprised of a cylindrical structure. Of course other cross sectional structures of elastomer spring 20 would be operable in this embodiment such as squares or multiple edges such as octagons, but as elastomer spring 20 is located within base wall 24, a cylindrical structure would be preferred.

Referring now to FIGS. 10, 11, and 12, three embodiments of base insert 21 are shown.

In FIG. 10, base insert 21A is shown as comprising a generally circular main section 41A, with wing section 43A extending laterally therefrom and wing section 45A extending laterally therefrom at an angle of about 180 degrees from wing section 43A. In FIG. 3, wing section 31 of base insert 21 would be visible through opening 31 in base structure 12 base wall 24. Wing section 33 would have a loading information number or other identifier imprinted to be visible through opening 31.

Similarly, base insert 21A would be preselected of a thickness TA that would be as thin as possible to accomplish the necessary support for spring 20 which itself would be selected of a length and compression to accomplish the desired load support for side bearing 10.

In this embodiment, thickness of base insert 21A-TA would be 0.11 inch (0.28 cm) and a complementary designed spring 20 would have a pre-compressed height of 5.30 inch, (13.5 cm) a setup height of 4.45 inch (11.3 cm) and a fully compressed height of 3.82 inch (9.7 cm).

In FIG. 11, base insert 21B is shown as comprising a generally circular main section 41B, with wing section 43B extending laterally therefrom and wing section 45B extending laterally therefrom at an angle of about 180 degrees from wing section 43B. In FIG. 3, wing section 31 of base insert 21 would be visible through opening 31 in base structure 12 base wall 24. Wing section 33 would have a loading information number or other identifier imprinted to be visible through opening 31.

Similarly, base insert 21B would be preselected of a thickness TB that would be a bit thicker than thickness TA to accomplish the necessary support for spring 20 which itself would be selected of a length and compression to accomplish the desired load support for side bearing 10.

In this embodiment, thickness of base insert 21B-TB would be 0.178 inch (0.45 cm) and a complementary designed spring 20 would have a pre-compressed height of 5.30 inch, (13.5 cm) set up height of 4.38 inch (11.1 cm) and a fully compressed height of 3.75 inch (9.5 cm).

In FIG. 12, base insert 21C is shown as comprising a generally circular main section 41C, with wing section 43C extending laterally therefrom and wing section 45C extending laterally therefrom at an angle of about 180 degrees from wing section 43C. In FIG. 3, wing section 31 of base insert 21 would be visible through opening 31 in base structure 12 base wall 24. Wing section 33 would have a loading information number or other identifier imprinted to be visible through opening 31.

Similarly, base insert 21C would be preselected of a thickness TC that would be as thin as possible to accomplish the necessary support for spring 20 which itself would be selected of a length and compression to accomplish the desired load support for side bearing 10.

In this embodiment, thickness of base insert 21C-TC would be 0.33 inch (0.84 cm) and a complementary designed spring 20 would have a pre-compressed height of 5.30 inch, (13.5 cm) a set up height of 4.23 inch (10.7 cm) and a fully compressed height of 3.60 inch (9.1 cm). 

What is claimed is:
 1. A side bearing for use in a railway car truck, the side bearing comprising: a base section having a base bottom portion and a base wall structure extending generally upward from the base bottom portion, the base wall structure forming a base receiving structure having an open top, a spring positioned in the base receiving structure of the base section, the spring having a preselected non-compressed height, a cap having a generally flat top portion and a cap wall structure extending generally downward from the top portion, the cap wall structure forming a cap receiving structure having an open bottom, and a base insert positioned within the base receiving structure, the base insert comprising a main section having a top surface, the main section having a preselected thickness, and wherein the spring has a bottom surface supported on the top surface of the main section of the base insert.
 2. The side bearing of claim 1 wherein the base insert is a unitary structure having a generally cylindrical main section, a first wing section extending laterally from the main section, a second wing structure extending laterally from the main section at an angle of about 180 degrees from the first wing section, and wherein the main section of the base insert has a pre-determined thickness.
 3. The side bearing of claim 2 wherein the base insert is comprised of a structural plastic.
 4. The side bearing of claim 2 wherein the thickness of the main section of the base insert varies with a predetermined load rating of the base insert.
 5. The side bearing of claim 2 wherein the thickness of the main section of the base insert varies between 0.11 inch (0.28 cm) and 0.33 inch (0.84 cm).
 6. The side bearing of claim 2 wherein the base wall structure of the base section of the side bearing has an opening therein, and wherein the first wing section of the base insert has an indication of a load rating therein, such that the load rating of the base insert is visible through the opening in the base wall structure.
 7. The side bearing of claim 1 wherein the spring is comprised of a generally cylindrical shaped, unitary elastomer structure.
 8. The side bearing of claim 7 wherein the spring includes a bottom surface, and the bottom surface of the spring contacts and is supported by the top surface of the main section of the base insert.
 9. The side bearing of claim 7, wherein the base insert has a thickness of 0.11 inch (0.28 cm), the spring has a pre-compressed height of 4.45 inch (11.3 cm), and the spring has a fully compressed height under maximum load of 3.82 inch (9.7 cm).
 10. The side bearing of claim 7, wherein the base insert has a thickness of 0.33 inch (0.84 cm), the spring has a pre-compressed height of 4.23 inch (10.7 cm) and the spring has a fully compressed height under maximum load of 3.60 inch (9.1 cm).
 11. The side bearing of claim 7 wherein the base insert has a thickness of 0.178 inch (0.45 cm), the spring has a pre-compressed height of 4.38 inch (11.1 cm) and the spring has a fully compressed height under maximum load of 3.75 inch (9.5 cm).
 12. A side bearing for use in a railway car truck, the side bearing comprising a base section having a base bottom portion and a base wall structure extending generally upward from the base bottom portion, the base wall structure forming a base receiving structure having an open top, a spring positioned in the base receiving structure of the base section, the spring having a pre-selected, non-compressed height, a cap having a generally flat top portion and a cap wall structure extending generally downward from the top portion, the cap wall structure forming a cap receiving structure having an open bottom, and a base insert positioned within the base receiving structure, the base insert comprising a generally circular main section of a predetermined thickness, the main section having a top surface and a generally cylindrical wall extending upwardly from the main section to form an upwardly facing base insert receiving structure.
 13. The side bearing of claim 12 wherein the spring has a bottom surface supported on the top surface of the main section of the base insert.
 14. The side bearing of claim 12 wherein the base insert is a unitary structure having a generally cylindrical main section, a first wing section extending laterally from the main section, a second wing structure extending laterally from the main section at an angle of about 180 degrees from the first wing section, and wherein the main section of the base insert has a pre-determined thickness.
 15. The side bearing of claim 14 wherein the base insert is comprised of a structural plastic.
 16. The side bearing of claim 14 wherein the thickness of the main section of the base insert varies with a predetermined load rating of the base insert.
 17. The side bearing of claim 14 wherein the thickness of the main section of the base insert varies between 0.11 inch (0.28 cm) and 0.33 inch (0.84 cm).
 18. The side bearing of claim 14 wherein the base wall structure of the base section of the side bearing has an opening therein, and wherein the first wing section of the base insert has an indication of a load rating therein, such that the load rating of the base insert is visible through the opening in the base wall structure.
 19. The side bearing of claim 12 wherein the spring is comprised of a generally cylindrical shaped, unitary elastomer structure. 